Abstract Regioselectivity of visible-light-induced transformations a range (hetero)aryl alkyl-substituted ketones bearing several competitive reactive sites ( ? -carbonyl, benzyl and aromatic ring) with N- bromosuccinimide (NBS) was studied under solvent-free reaction conditions (SFRC) in the absence inert-gas atmosphere, radical initiators catalysts. An 8-W energy-saving household lamp used fo...

The cyclization of 2,5-cyclohexadienones tethered to activated methylene groups was studied. The substitution around the cyclohexadienone ring serves to regioselectively direct these cyclizations based primarily on electronic effects. In the case of brominated substrates, these reactions proceed to give highly unusual electron-deficient tricyclic cyclopropanes. By using a Cinchona alkaloid-base...

A novel type of anti and syn isomers of a pentacyclic compound consisting of two thiophene rings and one pyrrole ring were efficiently synthesized from benzo[b]thiophene, and the anti isomer exhibits better charge transport and OFET properties compared with the syn isomer and its N-hexyl substitution.

New 1,4- and 2,4-substituted 1,2,3-triazole derivatives were synthesized and tested as potential BK(Ca) channel openers, as a part of a research program, which hypothesizes a pharmacophoric structure containing the 1,2,3-triazole ring. The structure-activity relationships were studied introducing some structural changes concerning molecular geometry and the presence of a hydrogen bond donor as ...

Novel, efficient and mild preparation of 7- and 8-membered cyclic di- and 10-membered cyclic tripeptides containing α-, β- or γ-amino acid residues is effected by a Staudinger-mediated ring closure. Medium-sized cyclic di- and tripeptides--recognized as difficult targets--were obtained in moderate to good yields according to a straightforward sequence. Empirical force-field calculations were un...

The crystal structures of 5-(5-furan-2-yl)-2'-deoxyuridine (II), 5-(5-bromofuran-2-yl)-2'-deoxyuridine (IV) and 5-(3-bromothien-2-yl)-2'-deoxyuridine (V) have been studied in order to explain the different affinity of the compounds for the herpes simplex virus type 1 (HSV-1) thymidine kinase. These compounds present a variable affinity according to the position of the heteroatom substituting th...

For a ring R, R[x] is a left nearring under addition and substitution, and we denote it by (R[x], +, ◦). In this note, we show that if nil(R) is a locally nilpotent ideal of R, then nil(R[x], +, ◦) = nil(R)0[x], where nil(R) is the set of nilpotent elements of R and nil(R)0[x] is the 0-symmetric left nearring of polynomials with coefficients in nil(R). As a corollary, if R is a 2-primal ring, t...

Treatment of N-benzyl benzamides with a strong base (LDA or t-BuLi) followed by irradiation with a 500 W tungsten lamp provides, according to the substitution pattern of the starting amides, either norcaradienes or cycloheptadienones by overall insertion of the N-benzyl group into the benzamide's aromatic ring system. Chiral benzamides undergo the ring expansion with high (sometimes complete) s...

-The hydrolysis of several ring substituted methyl benzoates was investigated in aqueous solution over a pH range of 3-10. Both the pH dependence (at pH > 5) and the variation of hydrolysis rates with ring substitution are consistent with a mechanism involving the addition of hydroxide ion to the ester carbonyl group. Extrapolation of the rate data to a pH and temperature that would be consiste...

Cyclobutanols undergo an oxidative ring expansion with Co(acac)2 and triplet oxygen to give 1,2-dioxanols. The formation of alkoxy radical drives the regioselective cleavage on more substituted side before insertion molecular oxygen. reaction is particularly effective secondary cyclobutanols but works also certain tertiary alcohols. Further substitution neutral nucleophiles under catalytic Lewi...